The Habituation reference article from the English Wikipedia on 24-Apr-2004
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Habituation

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Habituation is an example of non-associative learning in which there is a progressive diminution of behavioural response probability with repetition of a stimulus. It is another form of integration. An animal first responds to a sensory stimulus, but if it is neither rewarding or harmful the animal learns to suppress its response through repeated encounters. This learned suppression of response is habituation.